Some types of heart arrhythmia may result in lessening blood flow, thus reducing the amount of blood pumped to the various parts of the body. Some arrhythmias may even result in a Sudden Cardiac Arrest (SCA). SCA leads to death very quickly, unless treated in the interim.
People who have had a heart attack have an increased risk of SCA, and therefore it is recommended that they receive an Implantable Cardioverter Defibrillator (“ICD”). An ICD has electrodes that continuously monitor the person's electrocardiogram (“ECG”). If certain types of heart tachyarrhythmia are detected, then the ICD delivers electrical therapy through the heart.
People with increased risk of an SCA are sometimes given a wearable external defibrillator system. The recipients typically include those who have had a heart attack, but have not yet had an ICD implanted. A wearable defibrillator system typically includes a vest or harness that is worn by the person. The system includes a defibrillator and electrodes that are attached to the vest or harness. Typically the system monitor the person's ECG via the electrodes continuously. If a heart tachyarrhythmia is detected, then the defibrillator delivers the appropriate electrical discharge through the heart.
A problem is that compliance by the person is often not full. While the person has the system, they often do not wear it because they find it cumbersome and uncomfortable. The issue of improving compliance has been addressed, for example in US Patent Application No. 20120283794.
A root of the discomfort is from the fact that the electrodes of the wearable system have to be making good electrical contact continuously with the person's skin, so that the person's ECG can be monitored continuously. The problem has been addressed, for example in U.S. Pat. No. 6,546,285, titled LONG TERM WEAR ELECTRODE FOR DEFIBRILLATION SYSTEM. The latter patent teaches, among other things, to move the electrodes to different places on the person's skin at different times, and/or to use a hydrogel for the electrodes that includes a therapeutic agent which promotes skin health.